How to reuse calculated columns avoiding duplicating the sql statement?

Question

I have a lots of calculated columns and they keep repeting themselves, one inside of the others, including nested cases statements.

There is a really simplified ver

Answer 1

You could try something like this.

SELECT 
    A.Val AS A, 
    B.Val AS B, 
    C.Val AS C 
FROM MYTABLE
  cross apply(select 1 + 2) as A(Val)
  cross apply(select A.Val + 3) as B(Val)
  cross apply(select B.Val * 7) as C(Val)